Low-temperature sintered Li2ZnSiO4-Bi2O3-TiO2 ceramics with improved dielectric properties and temperature stability

As the communications industry continues to develop, low temperature co-fired ceramics are used as resonators in multilayer chip components of integrated circuits. In order to co-fire with the metal, it is necessary to reduce the sintering temperature of ceramics to below 960 °C. In order to rule out the impact of changes in the operating temperature of the ceramic material, we need to adjust the resonant frequency temperature coefficient to near zero. This paper discusses the application of a temperature-stable low-temperature sintered dielectric material derived from Li 2 ZnSiO 4 (LZS) in low-temperature co-fired ceramics (LTCC). The addition of the low melting point oxide Bi 2 O 3 resulted in a significant reduction of the sintering temperature and improvement of the densification of LZS ceramics, where the sintering temperature was reduced from 1200 °C to 900 °C. The relative density and microwave dielectric properties (dielectric constant ε r , quality factor Q × f and temperature coefficient of resonant frequency τ ƒ ) of LZS- x Bi 2 O 3 ( x  = 0, 3, 6, 9, 12 mol%) ceramics sintered at different temperatures increase and then decrease with increasing Bi 2 O 3 content. The best performance was obtained when the Bi 2 O 3 addition was 9 mol% (ε r  = 6.87, Q × f = 28,151 GHz, τ ƒ  = - 85.2 ppm/°C). By increasing the amount of TiO 2 added to LZS-9 mol%Bi 2 O 3 , the τ ƒ value of the ceramic system can be continuously increased, which is effectively adjusted to near zero. The best integrated dielectric properties of the LZS-Bi 2 O 3 -TiO 2 ceramic system (ε r  = 8.9, Q × f = 22.982 GHz, τ ƒ  = - 8.34 ppm/°C) are obtained when the TiO 2 addition is 30 wt%. This suggests that LZS-Bi 2 O 3 -TiO 2 ceramics have potential for low-temperature co-fired ceramics (LTCC) applications.